Each surgeon has their own regimen and it may vary from patient to patient and each patient's risk factors. My surgeon did not make her patients completely stop Estrogen, but has them drop to what will be their post-op recommended dosage. A slight snag on that one for me was that her post op dosage is twice what my endo was giving me pre-op, and post op, my endo still wants and prescribes HER dose for me that has not changed. (She did call my surgeon's office on the subject, she won! The fact I am doing great on both sides of the knife is all I care about.) I did have to stop taking Spiro and one other prescribed hypertension medication two weeks before the surgery, and even my PCP agreed with those going out until after the surgery.
Maybe you get the picture that I had more than ONE of my doctors involved in my health medications for some time, and I know that with my health risks, it was not just desirable, it was damn well necessary to keep me in any form of good health. My heath is better now than it has been for over half a century!!
On the blood loss issue, I have a interesting twist to it, but one which gives me an indicator of how much blood I did lose. I have a genetic condition where I retain a toxic level of an iron compound in my blood stream unless I have 500ml's of blood simply bled out of me every three to four months based on regular testing. The blood just gets trashed since it would be toxic for other people to get in a transfusion, but the compound levels are controlled that way. Eight weeks after my surgery I was scheduled to have another one of my "blood withdraws" and we went ahead with it. Three weeks after when I had a blood test, the compound level was half of what my hematologist wants to see, and so she figures that I lost nearly the 500ml's plus what ever blood cell volume I had replaced in the 6 weeks following my surgery. Looking at 500ml's of blood in a bottle is impressive, imagining that much was on your underwear over an extended time can make your tummy a little queasy!!
Believe me, you will be too darn miserable and much too busy after surgery to even think about fluctuating hormone levels, there were days I did not even have the energy to take the pills I needed to nor the attitude, which I could not attribute to hormone deficiency, only Advil deficiency!! Good luck doing it your way, but another side note, the surgeons do and can talk to each other, and still make different decisions. Your surgeon is GOD for the time you are under their care.